<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .parent{
            width: 300px;
            height: 300px;
            background-color: #ccc;
            /* 水平居中 */
            margin: 0 auto;
            display:flex;
      
        }
        .parent>div{
            width: 60px;
            height: 60px;

        }
        /* order值越大越靠后 */
       .parent>div:nth-child(2){
      /* 给弹性元素设置宽度 默认值auto 优先级高于width */
      /* flex-basis: 120px; */
      /* flex:flex-grow flex-shrink flex-basis 简写
       默认值0 1 auto */
      /* flex:0 1 auto; */
      flex:1;
       }
      .parent>div:last-child{
        flex:2;
      }
    </style>
</head>
<body>
    <div class="parent">
        <div class="div1" style="background-color: red;">弹性元素1</div>
        <div class="div2" style="background-color: green;">弹性元素2</div>
        <div class="div3" style="background-color: blue;">弹性元素3</div>
    </div>
</body>
</html>